1. From the Department of Biochemistry (J.F.W.K., T.L.) and the Cardiovascular Research Institute (S.J.H.W., T.L.), Maastricht University, 6200 MD Maastricht, The Netherlands; and the Medtronic Bakken Research Center B.V. (A.D., M.V., M.H.), 6229 GW Maastricht, The Netherlands.